Euphonious is Cube's newest group, a duo group comprising of Julia Chen and Melody Liu, mentored by Yong Junhyung. The pair takes part in writing the lyrics, composing, and taking an active interest in learning how to produce their music as well. Their debut mini-album titled Euphoria has three songs all written, produced and sung by the girls.

Melody though has an interesting relationship with her mentor at Cube. They'd been dating while she was a trainee, but when she anonymously tries out for Junhyung's project group and gets in they cut it off. Both deciding it'd be best to keep things strictly professional rather than play the dangerous game of dating in their situation.

Melody’s antics with his little sister and her playful personality cause the pair to disagree occasionally while trying to forget how they felt. Finding the delicate balance in idol life isn't easy, just as things get started and new friends are made rocky ground is hit. Despite her good friendship with Jackson, she and Mark seem to fight at each and every opportunity.